JP2011003714A - Exposure method, mask and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expose an isolation pattern including a plurality of isolation patterns, for example, with high accuracy by a progressive focal point exposure method.SOLUTION: An exposure method that exposes a wafer W, with an illumination light IL for light exposure via a pattern of a reticle R and a projection optical system PL, includes a step of setting an exposure condition of at least one of an inclination angle θp of an exposure surface of the wafer W to an image surface PW1 for the projection optical system PL, and a moving direction of the wafer W along the exposure surface, depending on a pattern shape thereof and an asymmetry illumination properties of the illumination light IL; and a step of exposing the pattern image onto the wafer W, which inclines at the inclination angle θp, and carrying out movement of the wafer W and movement of the reticle R, in a direction corresponding to the moving direction thereof in synchronization.

Description

  The present invention relates to an exposure method for exposing an object with exposure light via a pattern and a projection optical system, and is applicable to, for example, the case where exposure is performed by a progressive focus exposure method. Furthermore, the present invention relates to a mask that can be used when exposure is performed, for example, by a progressive focus exposure method, and a device manufacturing method using the exposure method.

  For example, in an exposure apparatus used in a lithography process for manufacturing an electronic device (microdevice) such as a semiconductor device, in order to increase the resolution of the projection optical system, the exposure wavelength λ is shortened and the projection optical system is used. The numerical aperture NA has been increased. On the other hand, the depth of focus (DOF) of the projection optical system is proportional to the exposure wavelength λ and inversely proportional to the square of the numerical aperture NA. Therefore, if the exposure wavelength λ is simply shortened and the numerical aperture NA is increased, the depth of focus becomes shallower. There is a risk of passing. For this reason, when the pattern to be exposed is a periodic pattern such as a circuit portion of a memory, for example, a so-called modified illumination method can be used to substantially increase the depth of focus while maintaining high resolution. It has been broken.

  On the other hand, when the pattern to be exposed is an isolated pattern, for example, a contact hole pattern, the image plane of the projection optical system and the substrate to be exposed (wafer or the like) in the optical axis direction of the projection optical system are relatively exposed during exposure. It is known that the apparent depth of focus of a projection optical system can be substantially increased by a progressive focus exposure method that changes the positional relationship continuously or intermittently. The progressive focus exposure method is sometimes called a flex method or a CDP exposure method (or a DP exposure method). In addition, when the progressive focus exposure method is applied in the scanning exposure method in which the reticle (mask) and the substrate are moved synchronously relative to the projection optical system at the time of exposure, the image plane of the projection optical system is applied during the scanning exposure. On the other hand, the substrate is driven so that the exposure surface of the substrate moves along a plane intersecting at a predetermined inclination angle (see, for example, Patent Document 1).

JP 2007-294550 A

  Recently, as a pattern to be exposed, an isolated pattern in which a plurality (for example, two) of isolated patterns having the same shape are arranged close to each other may be used. When such an isolated pattern is exposed by the scanning exposure method and the progressive focus exposure method, for example, when the size of the images of the plurality of isolated patterns is different from each other due to slight asymmetry of the exposure light. I know that there is.

  In view of such circumstances, the present invention provides, for example, an exposure technique that can expose an isolated pattern including a plurality of isolated patterns with a progressive focus exposure method with high accuracy, and a device manufacturing technique that uses this exposure technique. Objective. It is another object of the present invention to provide a mask that can be used for exposing the isolated pattern with a progressive focus exposure method with high accuracy.

  An exposure method according to the present invention is an exposure method in which an object is exposed with exposure light through the mask and a projection optical system by synchronously moving a mask on which a pattern is formed and the object in a predetermined direction. Depending on the asymmetric illumination characteristics of the exposure light with respect to the image plane of the projection optical system and at least one of the tilt angle of the exposure surface of the object and the moving direction of the object along the tilt direction of the exposure surface of the object A step of setting the exposure condition of the object, and exposing the image of the pattern by the projection optical system on the object inclined at the inclination angle with respect to the image plane, and along the inclination direction of the object A step of exposing the object in synchronization with the movement in the predetermined direction and the movement of the mask along the object plane of the projection optical system in a direction corresponding to the predetermined direction. It is intended.

Further, the mask according to the present invention exposes an image of the mask pattern on the object inclined at a predetermined inclination angle with respect to the image plane of the projection optical system, while the image of the projection optical system is exposed at the inclination angle of the object. In order to expose the object by synchronizing the movement of the mask in the predetermined direction along the inclined direction and the movement of the mask in the direction corresponding to the predetermined direction along the object plane of the projection optical system. According to the asymmetric illumination characteristics of the exposure light with respect to the predetermined direction and the exposure condition of at least one of the inclination angle and the moving direction of the object along the inclination direction,
The shape of the pattern is corrected.

  A device manufacturing method according to the present invention includes forming a pattern of a photosensitive layer on a substrate using the exposure method of the present invention, and processing the substrate on which the pattern is formed.

  According to the exposure method of the present invention, when an isolated pattern including a plurality of isolated patterns is an object to be exposed, for example, according to the shape of the isolated pattern and the asymmetric illumination characteristics of the exposure light, At least one exposure condition of the tilt angle of the exposure surface of the substrate and the moving direction along the exposure surface when the focus exposure method is applied is set. Therefore, the isolated pattern can be exposed with high accuracy by the progressive focus exposure method.

  Further, according to the mask of the present invention, for example, when an isolated pattern including a plurality of isolated patterns is formed, for example, the shape of the isolated pattern, asymmetric illumination characteristics of exposure light, and progressive focus exposure The shape of the isolated pattern is corrected in accordance with at least one exposure condition in the inclination angle of the exposure surface of the substrate and the moving direction along the exposure surface when the method is applied. Therefore, the isolated pattern can be exposed with high accuracy by the progressive focus exposure method.

It is a perspective view which shows schematic structure of the exposure apparatus used by an example of embodiment. (A) is a diagram showing a schematic configuration of the optical system of the exposure apparatus in FIG. 1, and (B), (C), (D), (E), and (F) are exposure regions 18W in FIG. 2 (A). It is a figure which shows the shape of the secondary light source on the illumination pupil plane of the illumination light which injects into the position where Y direction differs. 1A is a diagram showing a schematic configuration of a main part of the exposure apparatus in FIG. 1 when exposure is performed by a progressive focus exposure method, and FIG. 3B is an enlarged plan view showing a part of the pattern of the reticle R in FIG. , (C), (D), (E), (F), and (G) are enlarged views showing changes in the pattern image exposed on the wafer W in FIG. 3 is an enlarged view showing an image of a pattern exposed on a wafer W. FIG. (A) is a diagram showing a schematic configuration of the main part of the exposure apparatus of FIG. 1 when exposure is performed with a progressive focus exposure method at different tilt angles, and (B) is a part of the pattern of the reticle R of FIG. 4 (A). (C), (D), (E), (F), and (G) are enlarged views showing changes in the pattern image exposed on the wafer W in FIG. (H) is an enlarged view showing an image of a pattern exposed on the wafer W. FIG. FIG. 5A is a view showing a schematic configuration of a main part of the exposure apparatus of FIG. 1 when exposure is performed with a progressive focus exposure method at different tilt angles, and FIG. 5B is exposed on the wafer W of FIG. (C) is an enlarged view showing a pattern image, and (C) shows the relationship between the defocus width at the end in the scanning direction of the exposure region and the difference in line width of the image of the pattern to be exposed when the exposure is performed by the progressive focus exposure method. It is a figure which shows an example. It is a flowchart which shows the exposure method of an example of embodiment. (A) is an enlarged view showing a part of a pattern to be exposed in another example of the embodiment, (B) is an enlarged view showing an image of the pattern of FIG. 7 (A), and (C) is a line width corrected. (D) is an enlarged view showing an image of the pattern of FIG. 7 (C). It is a flowchart which shows an example of the manufacturing process of an electronic device.

Hereinafter, an exemplary embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a scanning exposure type exposure apparatus 100 including a scanning stepper (scanner) according to the present embodiment. In FIG. 1, an exposure apparatus 100 includes an exposure light source (not shown) and an illumination optical system ILS that illuminates a reticle R (mask) with exposure illumination light (exposure light) IL emitted from the exposure light source. ing. Further, the exposure apparatus 100 projects a reticle stage RST that holds and moves the reticle R, and illumination light IL emitted from the reticle R onto a wafer W (substrate) coated with a photoresist (photosensitive material). An optical system PL, a wafer stage WST that positions and moves the wafer W, a main control system 2 that includes a computer that controls the overall operation of the apparatus, and other drive systems are provided.

  Hereinafter, the Z-axis is taken in parallel with the optical axis AX of the projection optical system PL, the X-axis and the Y-axis are taken in two orthogonal directions within a plane (substantially a horizontal plane), and the X-axis, Y-axis, and Z-axis are taken. The description will be made assuming that the rotation (inclination) directions around the axis parallel to the axis are the θx, θy, and θz directions, respectively. In the present embodiment, the scanning direction of reticle R and wafer W during scanning exposure is a direction parallel to the Y axis (Y direction).

An ArF excimer laser (wavelength 193 nm) is used as the exposure light source. Other exposure light sources include ultraviolet pulse laser light sources such as KrF excimer laser (wavelength 248 nm), harmonic generation light source of YAG laser, harmonic generator of solid-state laser (semiconductor laser, etc.), discharge lamp such as mercury lamp, etc. Can also be used.
The illumination optical system ILS includes an illuminance uniformizing optical system including an optical integrator (a fly-eye lens, a rod integrator, a diffractive optical element, etc.) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. It includes an integrator sensor that monitors the intensity of the illumination light IL, a reticle blind (variable field stop), a condenser optical system, and the like. Further, the aperture stop 7A is set by a setting mechanism (not shown) on the pupil plane (illumination pupil plane) PIL in the illumination optical system ILS according to illumination conditions such as normal illumination, annular illumination, or quadrupole (or dipole) illumination. An aperture stop 7B in which a ring-shaped aperture is formed, or an aperture stop 7C in which four or more apertures are formed, etc. are installed. In FIG. 1, an aperture stop 7B for annular illumination is provided on the illumination pupil plane PIL. For example, when the shape of the secondary light source on the illumination pupil plane PIL can be accurately defined by a diffractive optical element or the like, it is not always necessary to install the aperture stops 7A to 7C.

  Illumination optical system ILS illuminates rectangular illumination area 18R elongated in the X direction (non-scanning direction) on pattern area PA with illumination light IL on the pattern surface (reticle surface) of reticle R with illumination light IL. The reticle blind of the illumination optical system ILS is disposed at a position slightly defocused from a surface PI1 optically conjugate with the reticle surface (see FIG. 2A), and a fixed blind 9 having a rectangular opening formed therein. In order to open and close the illumination area 18R in the Y direction during one scanning exposure that is arranged on the plane PI1 conjugate with the reticle surface and moves the reticle R in the + Y direction or the -Y direction, the opening of the fixed blind 9 is opened. A pair of movable blinds 8A and 8B that open and close and a pair of movable blinds (not shown) for defining the position and width in the X direction of the illumination region 18R are provided. The operations of the movable blinds 8A and 8B are controlled by the stage drive system 4.

  In FIG. 1, under illumination light IL, a circuit pattern in the illumination area 18R of the reticle R passes through a projection optical system PL that is telecentric on both sides (or one side telecentric on the wafer side). And a projection area 18W (an area conjugate to the illumination area 18R) on one shot area SA on the wafer W. The wafer W is obtained by applying a photoresist on a base material such as a disk-shaped silicon having a diameter of 200 mm or 300 mm, for example. The projection optical system PL is, for example, a refractive system, but a catadioptric system or the like can also be used. The reticle surface is arranged on the object plane of the projection optical system PL. However, when the progressive focus exposure method is used as will be described later, the surface (exposure surface) of the wafer W is relative to the image plane of the projection optical system PL. Move along an inclined surface.

  The reticle R is sucked and held on the reticle stage RST via a reticle holder (not shown). The reticle stage RST is mounted on an upper surface of the reticle base 12 parallel to the XY plane via an air bearing, and moves on the upper surface at a constant speed in the Y direction, as well as a position in the X direction, the Y direction, and a rotation angle in the θz direction. Make fine adjustments. As an example, two-dimensional positional information including the position of the reticle stage RST in at least the X and Y directions and the rotation angle in the θz direction includes an X-axis laser interferometer 14X and a Y-axis two-axis laser interferometer 14YA. , 14YB, and the measurement value is supplied to the stage drive system 4 and the main control system 2. The stage drive system 4 controls the speed and position of the reticle stage RST via a drive mechanism (not shown) based on the position information and the control information from the main control system 2.

  On the other hand, wafer W is sucked and held on wafer stage WST via wafer holder 20. Wafer stage WST includes an XY stage 24 and a Z tilt stage 22 that is placed on the XY stage 24 and holds the wafer W. The XY stage 24 is placed on an upper surface parallel to the XY plane of the wafer base 26 via an air bearing, and the upper surface moves in the X direction and the Y direction, and the rotation angle in the θz direction is corrected as necessary. . The Z tilt stage 22 individually drives, for example, three Z drive units 23A, 23B, and 23C (see FIG. 2A) that can be displaced in the Z direction, and the upper surface (wafer W) of the Z tilt stage 22 is driven. The position in the optical axis AX direction (Z position) and the inclination angles in the θx direction and the θy direction are controlled.

  In FIG. 1, the side surface of the projection optical system PL further includes an irradiation system 37 a and a light receiving system 37 b with the same configuration as that disclosed in, for example, US Pat. No. 5,448,332, etc. An oblique incidence type multi-point autofocus sensor 37 for measuring focus positions at a plurality of points on the exposure surface is provided. The stage drive system 4 is based on the measurement result of the autofocus sensor 37, and the Z tilt stage 22 is autofocused so that the exposure surface of the wafer W maintains a predetermined relationship with the image plane of the projection optical system PL. Drive.

  Two-dimensional position information including at least the position in the X direction, the Y direction, and the rotation angle in the θz direction of wafer stage WST (Z tilt stage 22) is, for example, two-axis laser interferometers 36XP and 36XF of the X axis. The measurement values are measured by a wafer side interferometer including two Y-axis laser interferometers 36YA and 36YB, and the measured values are supplied to the stage drive system 4 and the main control system 2. The position information is also supplied to the alignment control system 6. The stage drive system 4 determines the two-dimensional position of the XY stage 24 of the wafer stage WST via a drive mechanism (not shown) based on the position information and the control information from the main control system 2. Control.

  Further, the exposure apparatus 100 is a liquid immersion type, and supplies and recovers a liquid (pure water or the like) that transmits the illumination light IL to a local space between the optical member at the tip of the projection optical system PL and the wafer W. A local liquid immersion mechanism (not shown) is provided. As the local liquid immersion mechanism, a mechanism disclosed in, for example, US Patent Application Publication No. 2007/242247 or European Patent Application Publication No. 1420298 may be used.

  Further, on the side surface of the projection optical system PL, an off-axis type wafer alignment system 38 for measuring the position of the alignment mark on the wafer W is supported by a frame (not shown). The detection result of the wafer alignment system 38 is supplied to the alignment control system 6, and the wafer W can be aligned based on the detection result. Further, a reference member 28 is fixed in the vicinity of the wafer holder 20 on the Z tilt stage 22, and slit patterns 30 </ b> A and 30 </ b> B and a reference mark 32 are formed on the reference member 28. The aerial image measurement system 34 that receives the light flux that has passed through the slit patterns 30A and 30B is housed on the bottom surface of the reference member 28 in the Z tilt stage 22, and the detection signal of the aerial image measurement system 34 is supplied to the alignment control system 6. ing. The position of the image of the alignment mark (not shown) of the reticle R can be measured by the aerial image measurement system 34, and the alignment of the reticle R can be performed based on the measurement result. Further, the positional relationship (baseline) between the center (exposure center) of the pattern image of the reticle R and the detection center of the wafer alignment system 38 can be measured via the reference mark 32 on the reference member 28.

  At the time of exposure, liquid is supplied between the projection optical system PL and the wafer W, and an image of the pattern in the illumination area 18R of the reticle R by the projection optical system PL is exposed on one shot area on the wafer W. By moving the reticle R and the wafer W in the Y direction in synchronism with the projection magnification as the speed ratio, the pattern image of the reticle R is scanned and exposed in the shot area. Thereafter, the wafer stage WST is driven to move the wafer W stepwise in the X direction and the Y direction, and the scanning exposure operation is repeated, so that a step-and-scan method using a liquid immersion method is performed on the wafer W. A pattern image of the reticle R is exposed to each shot area.

  In this exposure, when the pattern of the reticle R to be exposed is an isolated pattern such as a contact hole or an isolated pattern in which a plurality of isolated patterns are arranged close to each other, the apparent focus of the projection optical system PL is Progressive focus exposure (or CDP exposure) may be used to increase the depth (DOF). Hereinafter, a scanning exposure method using the progressive focus exposure method in the exposure apparatus 100 of the present embodiment will be described.

  FIG. 2A shows a schematic configuration of a main part of the exposure apparatus 100 of FIG. 1 during scanning exposure using the progressive focus exposure method. In FIG. 2A, the illumination optical system ILS is a lens that guides the illumination light IL from the annular secondary light source 7BS formed in the aperture of the aperture stop 7B to the surface PI1 on which the movable blinds 8A and 8B are arranged. A system 10A and lens systems 10B and 10C for guiding the illumination light IL that has passed through the opening surrounded by the movable blinds 8A and 8B and the opening of the fixed blind 9 to the pattern surface of the reticle R are provided. Fixed blind 9 is arranged on a surface PI2 shifted from surface PI1 conjugate with the pattern surface of reticle R by −δZ1 in the −Z direction. In the following, it is said that the fixed blind 9 is defocused from the surface PI1. In FIG. 2A, an optical path bending mirror (not shown) in the illumination optical system ILS in FIG. 1 is omitted. Further, the fixed blind 9 may be disposed on a surface defocused in the + Z direction from the surface PI1.

  The pattern surface of the reticle R is disposed on the object surface of the projection optical system PL. As an example, the reticle R is scanned in the −Y direction B1 by the reticle stage RST. Normally, the reticle R is alternately scanned in the + Y direction and the −Y direction each time a different shot area on the wafer W is exposed. Further, for example, with respect to the image plane PW1 (a plane conjugate to the pattern surface of the reticle R) of the projection optical system PL having the front group lens system PLa and the rear group lens system PLb, the optical axis AX Assuming an inclined surface PW3 that passes through the axis parallel to the X axis and is inclined counterclockwise at an inclination angle θp, the exposure surface Wa of the wafer W is disposed on the inclined surface PW3. As an example, if the projection optical system PL forms an inverted image in the Y direction, the XY stage 24 of the wafer stage WST moves in the + Y direction B2 corresponding to the reticle stage RST.

  In this case, during the scanning exposure, the movable blinds 8A and 8B are fully opened, and the fixed blind 9 is defocused from the surface PI1, so that the best focus surface of the exposure region 18W that is an image of the opening of the fixed blind 9 is obtained. PW2 is at a position shifted from the image plane PW1 by the interval δZ2 in the −Z direction. Accordingly, in the areas 18Wa and 18Wc having the width ys at both ends in the Y direction (scanning direction) of the exposure area 18W on the wafer W, the illuminance of the illumination light IL gradually decreases toward the outside. The illuminance distribution in the Y direction of the light IL (the same applies to the illuminance distribution of the illumination region 18R) has a trapezoidal shape in which both end portions are inclined as indicated by the broken line 39. When the interval in the Y direction at the point where the height of the broken line 39 is ½ of the maximum height is the slit width YE of the exposure region 18W, the slit width YE is, for example, about 4 to 8 mm, and the illuminance distribution is inclined. The width ys of the portion is, for example, about several hundreds μm to 1 mm. The reason why the illuminance distribution in the Y direction of the exposure area 18W is trapezoidal is as follows. That is, a laser light source that emits light in the ultraviolet region, such as an excimer laser, generally emits pulse light, and the illumination light IL is pulse light. For this reason, when the illuminance distribution in the Y direction of the exposure region 18W changes stepwise, the number of irradiation pulses of the illumination light IL differs at different positions in the Y direction on the wafer W after scanning exposure, resulting in uneven exposure on the wafer W. May occur.

  Further, when the exposure surface Wa of the wafer W is inclined at an inclination angle θp with respect to the image plane PW1 as in the present embodiment, the exposure surface Wa of the reticle R is at the center (on the optical axis AX) of the exposure region 18W. Although it is at the best focus position (on the image plane PW1) of the pattern image, the exposure surface Wa is below and above the image plane PW1 at the ends of the exposure area 18W in the -Y direction and the + Y direction, respectively. The step Zcd, which is the difference in height (defocus width) in the Y direction at both ends in the Y direction of the exposure region 18W, is the regions 18Wa and 18Wc where the tilt angle θp (rad), the slit width YE, and the illuminance distribution are tilted. Is approximately as follows using the width ys.

Zcd = (YE + ys) θp (1)
Therefore, in the progressive focus exposure method, the driving amount of the Z tilt stage 22 (Z driving units 23A to 23C) of the wafer stage WST is gradually changed during the scanning exposure, so that the exposure surface Wa of the wafer W is always relative to the image plane PW1. The wafer W is scanned in the direction B3 along the inclined surface PW3 so as to coincide with the inclined surface PW3 inclined at the inclination angle θp. When the reticle R is scanned in the + Y direction, the wafer W is scanned such that the exposure surface Wa of the wafer W moves in the direction opposite to the direction B3 along the inclined surface PW3. As a result, each point on the wafer W moves in the Z direction with the width of the step Zcd (defocus width) around the image plane PW1 when passing through the exposure region 18W. Thereby, since the effect of progressive focus is obtained, the apparent depth of focus of the projection optical system PL with respect to the isolated pattern or the image of the isolated pattern is increased, and the isolated pattern or the isolated An image of a simple pattern can be exposed with high resolution.

  However, as in the present embodiment, the exposure surface Wa is away from the best focus surface PW2 of the opening image (exposure region 18W) of the fixed blind 9 (or the same in the lower portion), and the exposure surface Wa is the projection optical system. When tilted with respect to the PL image plane PW1, the opening angle of the illumination light IL incident on the exposure surfaces Wa of the regions 18Wa and 18Wc where the illuminance distribution at both ends of the exposure region 18W is tilted is parallel to the Z axis. Is not symmetrical in the Y direction (the shape of the secondary light source on the illumination pupil plane PIL of the illumination light IL becomes a part of the secondary light source 7BS of the aperture stop 7B), and telecentricity is not secured in that portion. . For example, the illumination light IL incident on the end portion in the −Y direction of the exposure region 18W is emitted from the region 7BSa at the end portion in the −Y direction shown in FIG. 2B among the secondary light sources 7BS on the illumination pupil plane PIL. Only the luminous flux produced. The illumination light IL1 incident on the point A1 in the −Y direction area 18Wa of the exposure area 18W is emitted from the area 7BSb on the half surface side in the −Y direction of the secondary light source 7BS shown in FIG. Only the luminous flux.

  On the other hand, the illumination light IL2 incident on an arbitrary point A2 in the region 18Wb where the illuminance distribution in the exposure region 18W is flat is a light beam emitted from the entire region of the secondary light source 7BS shown in FIG. Furthermore, the illumination light IL3 incident on the point A3 in the + Y direction area 18Wc of the exposure area 18W is only the light beam emitted from the + 7-direction half face area 7BSc of the secondary light source 7BS shown in FIG. It is. The illumination light IL incident on the end in the + Y direction of the exposure area 18W is only the light beam emitted from the area 7BSd at the end in the + Y direction of the secondary light source 7BS shown in FIG. Furthermore, in FIG. 2A, the illumination light IL1 incident on the point A1 is inclined counterclockwise with respect to an axis parallel to the Z axis as a whole, and the illumination light IL2 incident on the point A2 is totally Z. The illumination light IL3 that is parallel to the axis and incident on the point A3 is inclined clockwise with respect to an axis parallel to the Z axis as a whole. Accordingly, the illumination light IL1 incident on the −Y direction region 18Wa in the exposure region 18W has a counterclockwise inclination angle that increases as the incident position approaches the −Y direction (end). The illumination light IL3 incident on the + Y direction region 18Wc has a clockwise inclination angle that increases as the incident position approaches the + Y direction (end).

  Thus, when the progressive focus exposure method is performed in a state where the telecentricity of the illumination light IL is substantially symmetrically broken at both ends of the exposure region 18W, the exposure surface Wa is formed in the region 18Wa at the end in the −Y direction. Since the position is lower than the image plane PW1, the position of the image of the pattern of the reticle R is shifted in the + Y direction with respect to the −Y direction side of the area 18Wa. In the area 18Wc at the end in the + Y direction, the exposure plane Wa is the image plane PW1. Therefore, the position of the pattern image of the reticle R is shifted in the + Y direction with respect to the target position toward the + Y direction side of the region 18Wc. As described above, the imaging position of the image of the reticle R pattern is shifted in the same direction in the regions 18Wa and 18Wc at both ends of the exposure region 18W due to the deviation of the telecentricity of the illumination light and the inclination of the exposure surface Wa of the wafer W. This is an asymmetric illumination characteristic (asymmetry) of the illumination light IL in the present embodiment.

  Such asymmetry of the illumination light IL causes an optical proximity effect (OPE) when exposing an isolated pattern in which a plurality of (for example, two) isolated patterns are arranged in close proximity. ) Decreases the symmetry of the image exposed on the wafer W. 3A shows a schematic configuration of the main part from the reticle stage RST to the wafer stage WST in FIG. 2A, and FIG. 3B is formed on the reticle R in FIG. 3A. It is an enlarged plan view of a part of the pattern. As shown in FIG. 3B, the reticle R has two square contact hole patterns (hereinafter referred to as CH patterns) CH1 and CH2 in the Y direction (hereinafter referred to as CH patterns) with a light shielding film as a background. Twin hole patterns arranged at intervals b in the scanning direction) are formed. In the pattern area of the reticle R, a large number of twin hole patterns having substantially the same shape as the twin hole pattern made up of a pair of CH patterns CH1 and CH2 are formed at predetermined intervals in the X and Y directions. As an example, at the stage of projection images of the CH patterns CH1 and CH2, the width a is about 60 to 150 nm and the interval b is about 40 to 200 nm.

  In this case, in FIG. 3A, assuming that the reticle R is scanned in the -Y direction B1 and the wafer W is scanned in the direction B3 along the inclined surface PW3, an image of a twin hole pattern on the wafer W is exposed. When the predetermined exposed portion crosses the exposure area 18W in the + Y direction, the exposed portion has images CH1P, CH2P of the CH patterns CH1, CH2 as shown in FIGS. 3 (C) to 3 (G). Are continuously exposed. The dotted line images CHA and CHB indicate the target positions (design positions) of the CH patterns CH1 and CH2, and the original dotted line images CHA and CHB overlap the target positions. For convenience, it is shifted in the X direction. 3C shows an image immediately after the exposed portion enters the -Y direction region 18Wa, and FIG. 3D shows the exposed portion from the region 18Wa to the region 18Wb having a flat illuminance distribution. 3E is an image immediately after entering, FIG. 3E is an image when the exposed portion is in the center of the region 18Wb, and FIG. 3F is an image immediately after the exposed portion enters the region 18Wc in the + Y direction. FIG. 3G shows an image immediately before the exposed portion passes through the region 18Wc.

  In the region 18Wa in the −Y direction, the position of the projected image is shifted in the + Y direction toward the outer side. Therefore, the distance between the twin-hole pattern images CH1P and CH2P in FIG. In particular, the line widths in the X and Y directions of the image CH2P on the -Y direction side are widened. Note that the effect of increasing the line width is small for the image CH1P on the + Y direction side because the amount of light of the other image CH2P is small. In addition, in the central region 18Wb in FIG. 3E, the sizes of the images CH1P and CH2P are the same. Further, in the + Y direction region 18Wc, since the position of the projected image is shifted in the + Y direction toward the outer side, the interval between the twin hole pattern images CH1P and CH2P in FIG. In particular, the line width in the X and Y directions of the image CH1P on the + Y direction side becomes narrower than the design value due to the decrease. As for the image CH2P on the −Y direction side, the light amount of the other image CH1P is small, but the line width becomes somewhat narrow.

  Therefore, after scanning the wafer W along the direction B3, the twin hole pattern image formed on the exposed portion on the wafer W is the line of the image CH1P on the + Y direction side as shown in FIG. The width becomes narrower than the line width of the other image CH2P, and asymmetry occurs.

In FIG. 3A, the reticle R is scanned in the + Y direction B1V, the XY stage 24 of the wafer stage WST is scanned in the -Y direction B2V, and the wafer W is reversed to the direction B3 via the Z tilt stage 22. Even in the case of scanning in the direction B3V, the exposed image on the wafer W is exposed to the same image as in FIG.
The asymmetry of the line width of the image of the twin hole pattern described above is that the inclination angle θp of the exposure surface Wa (inclined surface PW3) of the wafer W with respect to the image surface PW1 (and the step Zcd at both ends of the exposure region 18W), The line widths a and intervals b of the CH patterns CH1 and CH2 vary, the average width ys of the regions 18Wa and 18Wc at both ends of the exposure region 18W, the illumination conditions of the illumination light IL, and the like.

  For example, FIG. 4A shows a case where the inclination angle θp1 of the exposure surface Wa (inclined surface PW3 ′) of the wafer W with respect to the image plane PW1 is smaller than the inclination angle θp of FIG. In FIG. 4A, the step Zcd1 at both ends of the exposure region 18W is also reduced in proportion to the inclination angle θp1. Also in this case, assuming that the reticle R is scanned in the −Y direction B1 and the wafer W is scanned in the direction B3 ′ along the inclined surface PW3 ′, the twin hole pattern (CH pattern) on the reticle R in FIG. When the exposed portion on the wafer W on which the image of CH1, CH2) crosses the exposure region 18W in the + Y direction, the exposed portion is shown in FIGS. 4C to 4G. The CH patterns CH1 and CH2 images CH1P and CH2P are continuously exposed (dotted line images CHA and CHB are target positions).

  In addition, in the −Y direction region 18Wa, the position of the projected image is shifted in the + Y direction toward the outer side. Therefore, the space bb1 between the twin-hole pattern images CH1P and CH2P in FIG. 4C is slightly smaller than the designed space. In particular, the line width of the image CH2P on the −Y direction side is increased by OPE. Further, in the + Y direction region 18Wc, the position of the projected image is shifted in the + Y direction toward the outer side. Therefore, the interval bb2 between the twin-hole pattern images CH1P and CH2P in FIG. 4G is slightly wider than the designed interval. In particular, the line widths in the X and Y directions of the image CH1P on the + Y direction side are slightly narrower than the design values due to the decrease in OPE.

  However, when the inclination angle θp1 of the exposure surface Wa is small as shown in FIG. 4A, the widths of the regions 18Wa and 18Wc at both ends of the exposure region 18W are substantially the same, and the CH pattern image CH2P in the −Y direction. The effect of widening the line width in the region 18Wa acts strongly on the area 18Wa, and the line width of the image CH2P becomes wide. On the other hand, in the CH pattern image CH1P in the + Y direction, the effect of increasing the line width in the region 18Wa is the same as the effect of reducing the line width in the region 18Wc, and the line width of the image CH1P does not change much. . As a result, after scanning the wafer W along the direction B3 ′, an image of the twin hole pattern formed on the exposed portion on the wafer W is an image on the −Y direction side as shown in FIG. The line width of CH2P is wider than the line width of the other image CH1P.

4A, even when the reticle R is scanned in the + Y direction and the wafer W is scanned in the direction B3V ′ opposite to the direction B3 ′ via the wafer stage WST, the exposed portion on the wafer W is also exposed. An image similar to that shown in FIG.
FIG. 5A shows a case where the sign of the inclination angle (−θp) of the exposure surface Wa of the wafer W with respect to the image plane PW1 is changed with respect to the case of FIG. That is, in the case of FIG. 5A, the exposure surface Wa is inclined by the angle θp clockwise with respect to the image plane PW1. At this time, the step Zcd at both ends of the exposure region 18W becomes a negative value from the equation (1). In FIG. 5A, in order to expose the images of the CH patterns CH1 and CH2 in FIG. 3B on the wafer W, for example, the reticle R is scanned in the + Y direction B1V, and the XY stage 24 of the wafer stage WST. Is scanned in the −Y direction B2V, and the exposure surface Wa of the wafer W is scanned in the direction B3V along the inclined surface PW3 having the inclination angle (−θp), as shown in FIG. The CH pattern image CH1P and the narrower CH pattern image CH2P are exposed. The image in FIG. 5B is obtained by switching the left and right sides of the image in FIG.

  As described above, when the twin hole pattern (CH pattern CH1, CH2) image of FIG. 3B is exposed by the scanning exposure method and the progressive focus exposure method, the line width in the Y direction of the image of the CH pattern CH1 is used as a reference. The relationship between the line width difference ΔCDY in the Y direction of the image of the CH pattern CH2 and the step Zcd at both ends in the Y direction of the exposure region 18W (or the inclination angle θp of the exposure surface Wa with respect to the image surface PW1) is shown in FIG. 5 (C) curve 40A. The sign of the line width difference ΔCDY is reversed when the sign of the step Zcd (sign of the tilt angle θp) is reversed. In the curve 40A, the line width difference ΔCDY increases once and then increases again when the step Zcd (or the inclination angle θp) increases. When the value of the interval b between the CH patterns CH1 and CH2 in FIG. 3B is increased, for example, the relationship between the line width difference ΔCDY and the step Zcd (or the inclination angle θp) is as shown by a dotted curve 40B. Become.

  Similarly, the relationship between the line width difference ΔCDX in the X direction of the image of the CH pattern CH2 with respect to the line width in the X direction of the image of the CH pattern CH1 is also determined to have a relationship with the step Zcd (or the inclination angle θp). be able to. The characteristics of the curves 40A, 40B, etc. in FIG. 5C depend on the shape of the twin hole pattern to be exposed, the illumination conditions, the step Zcd (defocus width or inclination angle θp) of the progressive focus exposure method, etc., for example It can be obtained in advance by computer simulation. Further, the characteristics can be obtained by measuring the line width of a pattern formed by a test print, for example, with a scanning electron microscope or the like.

  For example, when manufacturing a semiconductor device or the like, in the process of forming such a twin hole pattern, for example, it is required to reduce the difference in line width between two adjacent CH pattern images as much as possible. Hereinafter, when the twin hole pattern as shown in FIG. 3B is exposed using the progressive focus exposure method, the effect of the asymmetry of the illumination light is reduced, and the line width difference ΔCDX between the images of the two CH patterns is reduced. , ΔCDY will be described with reference to the flowchart of FIG.

  First, in step 101 of FIG. 6, as described above, the characteristic calculation unit in the main control system 2 performs exposure with various twin hole pattern shapes (line width a and interval b) to be exposed and progressive focus exposure. Step Zcd (or the tilt angle θp of the exposure surface Wa) at both ends of the exposure area 18W, the illumination conditions (the shape of the secondary light source on the illumination pupil plane PIL), the slit width YE and the illuminance distribution of the exposure area 18W A difference ΔCDX in the X direction and a difference ΔCDY in the Y direction (for example, curves 40A and 40B in FIG. 5C) of the line width of the two images of the twin hole pattern are calculated according to the width ys of the inclined region. To do. Instead of this calculation or in addition to this calculation, the difference in line width by the above test print may be measured.

  In the next step 102, the characteristics of the line width differences ΔCDX, ΔCDY obtained in step 101 are used as functions or tables such as the shape of the twin hole pattern and the step Zcd (or inclination angle θp) of the exposure region 18W, for example, the main control system 2 is stored in the storage device. In the next step 103, a reticle to be exposed (reticle R) is loaded onto the reticle stage RST of FIG. 2A, and alignment of the reticle R is performed using the aerial image measurement system 34 of FIG. In the next step 104, the first exposure control unit in the main control system 2 is, for example, the most apparent when the pattern of the reticle R is exposed by the progressive focus exposure method based on the twin hole pattern data of the reticle R. The absolute value Zcda of the step Zcd (defocus width) at both ends of the exposure area 18W is determined so that the depth of focus (DOF) can be increased. The absolute value of the step Zcd can be determined regardless of the asymmetry of the illumination light IL using, for example, a table obtained in advance.

  In the next step 105, the second exposure control unit in the main control system 2 determines the twin hole pattern based on the twin hole pattern data of the reticle R and the characteristics of the line width differences ΔCDX and ΔCDY stored in step 102. The step Zcd (or the tilt angle θp) of the exposure region 18W during scanning exposure so that the average value of the difference ΔCDX in the X direction and the difference ΔCDY in the Y direction of the line widths of the images of the two CH patterns CH1 and CH2 becomes small. Is determined. In this case, since the absolute value Zcda of the step Zcd is determined in step 104, the sign of the step Zcd is determined as follows, for example. That is, for example, assuming that the relationship between the difference ΔCDY in the Y direction of the line width of the image and the step Zcd is represented by the curve 40A in FIG. 5C, the pattern of the reticle R is determined from the data of the twin hole pattern. When it is known that the line width difference ΔCDY ′ due to the drawing error is a positive sign, the step Zcd is set so that the line width difference ΔCDY by the progressive focus exposure method becomes a negative value (−CDx). Set to negative -Zcda. In this case, the inclination angle θp is a clockwise angle as shown in FIG. 5A based on the equation (1). Actually, the sign of the final step Zcd is set based on the average value of the line width difference ΔCDX ′ in the X direction and the difference ΔCDY ′ (the same applies hereinafter).

  On the other hand, if it is known from the twin hole pattern data that the line width difference ΔCDY ′ due to the drawing error of the reticle R pattern has a negative sign, the line width difference ΔCDY by the progressive focus exposure method is positive. The step Zcd is set to a positive value Zcda so that the value becomes (CDx). Accordingly, the inclination angle θp also becomes a positive value. Thereby, the difference in the line width of the image of the twin hole pattern after exposure is reduced. The sign and value information of the step Zcd (or the inclination angle θp) determined in step 105 is supplied to the stage drive system 4 in FIG.

In step 105, the absolute value of the step Zcd itself is adjusted within a range (predetermined range) in which the effect of increasing the focal depth by the progressive focus exposure method does not change significantly so that the difference in line width becomes smaller. Also good.
In the next step 106, an unexposed wafer W coated with a photoresist is loaded onto the wafer stage WST in FIG. 2A, and the wafer W is aligned using the wafer alignment system 38 in FIG. In the next step 107, as shown in FIG. 2A, the exposure surface (surface) Wa of the wafer W is moved along the inclined surface PW3 inclined at an angle θp with respect to the image plane PW1, while the wafer W is moved. The operation of scanning and exposing the image of the pattern of the reticle R in one shot area and the operation of moving the wafer W stepwise in the X and Y directions are repeated, and the wafer W is processed by the step-and-scan method and the progressive focus exposure method. An image of the twin hole pattern of the reticle R is exposed to each shot area. After unloading the exposed wafer W in the next step 108, it is determined in step 109 whether there is a wafer to be exposed next. If there is an unexposed wafer, steps 106 to 108 are repeated. Then, when the unexposed wafer is exhausted in step 109, the exposure process is completed.

Effects and the like of this embodiment are as follows.
(1) In the exposure method using the exposure apparatus 100 of the present embodiment, the reticle R on which the pattern is formed and the wafer W are moved synchronously in the Y direction (scanning direction), so that the reticle R and the exposure light IL are used. In the exposure method in which the wafer W is exposed through the projection optical system PL, the asymmetric illumination characteristics of the illumination light IL in the Y direction (for example, telecentricity is present in the regions 18Wa and 18Wc at both ends of the exposure region 18W in FIG. 2A). The inclination angle θp of the exposure surface Wa of the wafer W with respect to the image plane PW1 of the projection optical system PL in accordance with the fact that the areas 18Wa and 18Wc are displaced in the opposite direction to the image plane PW1). Steps 104 and 105 for setting an exposure condition including an absolute value and a sign of (or step Zcd), and tilting with respect to the image plane PW1 at the set tilt angle θp While exposing an image of the pattern by the projection optical system PL on the exposed surface Wa of the wafer W, the movement of the wafer W in the Y direction along the tilt direction inclined by the tilt angle θp, and the projection optical system PL A step 107 of exposing the wafer W by performing movement of the reticle R along the object plane in the Y direction corresponding to the movement direction of the wafer W in synchronization.

  According to the present embodiment, when an isolated pattern including two isolated patterns (CH patterns CH1, CH2) is an exposure target, the shape of the isolated pattern and the asymmetric illumination characteristics of the illumination light IL are obtained. Accordingly, the exposure condition of the inclination angle θp when the progressive focus exposure method is applied is set so that the difference between the line widths of the images of the CH patterns CH1 and CH2 becomes small. Therefore, the isolated pattern can be exposed with high accuracy by the progressive focus exposure method.

The isolated pattern to be exposed may be a pattern in which three or more contact hole patterns are arranged close to each other, or any other plurality of patterns.
Further, as an exposure condition, instead of the tilt angle θp (step Zcd) or together with the tilt angle θp, the movement direction of the wafer W along the exposure surface Wa (tilt direction) (for example, the direction B3 in FIG. 3A). Alternatively, the direction B3V) may be considered.

(2) Further, the asymmetric illumination characteristics of the illumination light IL include the widths ys of the regions (defocused portions) 18Wa and 18Wc where the illuminance distributions at both ends in the Y direction (scanning direction) of the exposure region 18W are inclined. include. When the width ys is changed, for example, characteristics such as curves 40A and 40B representing the line width difference ΔCDY in FIG. 5C are also changed.
(3) The asymmetric illumination characteristic of the illumination light IL also includes information on the light intensity distribution (pupil plane asymmetry) on the pupil plane (or illumination pupil plane PIL) of the projection optical system PL of the illumination light IL. . Therefore, when the illumination conditions (annular illumination, quadrupole illumination, etc.) are switched, the characteristics such as the curves 40A, 40B in FIG. 5C are also changed accordingly.

  (4) Further, the steps 104 and 105 for setting the exposure conditions are performed in accordance with the asymmetric illumination characteristics of the illumination light IL and the line width a and interval b (shape information) of the twin hole pattern of the reticle R. Is set. Therefore, even when the pattern to be exposed is changed, the progressive focus exposure method can be applied so that the difference in the line width of the image of each exposed pattern is reduced.

When setting the exposure conditions, only at least one of the line width a and the interval b may be considered. Also in this case, the difference in the line width of the exposed pattern can be reduced.
(5) In steps 104 and 105 for setting the exposure conditions, the exposure conditions may be set according to the asymmetric aberration component included in the imaging characteristics of the projection optical system PL. As a result, even when, for example, dipole illumination is performed and an asymmetrical aberration component (for example, astigmatism (center astigmatism) on the optical axis) occurs in the imaging characteristics of the projection optical system PL, the asymmetrical The influence of the aberration component can be reduced.

  Next, another example of the embodiment of the present invention will be described with reference to FIG. In the exposure method of FIG. 6, the inclination angle θp of the exposure surface when using the progressive focus exposure method (or the step Zcd at both ends of the exposure region 18W) so that the difference in the line width of the image of the twin hole pattern after exposure becomes small. ) Was decided. In this embodiment, the shape of the pattern formed on the reticle R is corrected when the tilt angle θp (or the step Zcd) when using the progressive focus exposure method is determined, for example, under the condition that the depth of focus is the deepest. It shall be.

  That is, the reticle R pattern before correction is a twin hole pattern in which square CH patterns CH1 and CH2 having a line width a are arranged at an interval b as shown in FIG. When the progressive focus exposure method is applied at θp, the pattern exposed on the wafer W is, as shown in FIG. 7B, a first CH pattern having a width a1X in the X direction and a width a1Y in the Y direction. It is assumed that the image CH1P and the image CH2P of the second CH pattern having the width a2X in the X direction and the width a2Y in the Y direction (because it is an inverted image, the position in the Y direction is switched). It is assumed that the widths a2X and a2Y are larger than the widths a1X and a1Y. In this case, instead of the reticle R, as shown in FIG. 7C, a square CH pattern CH1 having a width a and a CH pattern CH2 having a width acX in the X direction and a width acY in the Y direction are arranged at an interval b. Reticle R1 is used. That is, the CH pattern CH2 of the reticle R1 is formed smaller than the pattern 41 before correction.

The relationship between the widths of the images CH1P and CH2P in FIG. 7B and the widths acX and acY of the CH pattern CH2 in FIG. 7C is as follows.
acX = a · a1X / a2X (2)
acY = a · a1Y / a2Y (3)
As a result, when the pattern of the reticle R1 in FIG. 7C is exposed by the progressive focus exposure method with the tilt angle θp, the pattern exposed on the wafer W is X as shown in FIG. Two images CH1P and CH2P having the same size of the width a1X in the direction and the width a1Y in the Y direction are obtained.

The effects and the like of this embodiment are as follows.
(1) The reticle R1 (mask) used in this embodiment is an illumination light for exposure on the exposure surface Wa of the wafer W tilted at a predetermined tilt angle θp with respect to the image plane PW1 of the projection optical system PL. A reticle used for exposing the wafer W by the scanning exposure method while exposing an image of the reticle pattern under the IL by the projection optical system PL, and an asymmetric illumination characteristic of the illumination light IL, and The pattern shape is corrected according to the exposure condition of the inclination angle θp.

  According to the reticle R1 of this embodiment, for example, when an isolated pattern including a plurality of isolated patterns is formed, for example, the shape of the isolated pattern, the asymmetric illumination characteristics of the illumination light IL, and the progressive focus The shape of the isolated pattern is corrected so that the line widths of the images of the plurality of isolated patterns become equal according to the exposure conditions including the tilt angle θp of the wafer W when the exposure method is applied. Therefore, the isolated pattern can be exposed with high accuracy by the progressive focus exposure method.

In this embodiment, the shape of the isolated pattern may be corrected based on the moving direction of the wafer W along the exposure surface.
(2) Further, the asymmetric illumination characteristic of the illumination light IL includes the width ys of the regions (defocus portions) 18Wa and 18Wc where the illuminance distribution at both ends in the scanning direction of the exposure region 18W is inclined. . When the width ys is changed, it is preferable that the shape of the pattern formed on the reticle R1 is also corrected.

(3) Further, the asymmetric illumination characteristic of the illumination light IL includes information on the light intensity distribution on the pupil plane (or illumination pupil plane PIL) of the projection optical system PL of the illumination light IL. Therefore, when the illumination conditions (annular illumination, quadrupole illumination, etc.) are switched, it is preferable that the shape of the pattern formed on the reticle R1 is also corrected accordingly.
(4) Also in this embodiment, the isolated pattern formed on the reticle to be exposed is a pattern in which three or more contact hole patterns are arranged close to each other, or any other plurality of patterns. Also good.

  When an electronic device (or microdevice) such as a semiconductor device is manufactured using the exposure method of the exposure apparatus of the above embodiment, the electronic device has a function / performance design of the electronic device as shown in FIG. Step 221 to be performed, Step 222 to manufacture a reticle (mask) based on this design step, Step 223 to manufacture a substrate (wafer) that is a base material of the device and apply a resist, and the exposure apparatus (exposure) of the above-described embodiment Method), a substrate processing step 224 including a step of exposing a reticle pattern to a substrate (photosensitive substrate), a step of developing the exposed substrate, a heating (curing) and etching step of the developed substrate, a device assembly step (dicing step) , Including processing processes such as bonding process and packaging process) And an inspection step 226, and the like.

  In other words, the device manufacturing method forms the pattern of the photosensitive layer on the substrate (wafer) using the exposure method of the above-described embodiment, and processes the substrate on which the pattern is formed (step 224). ). At this time, according to the exposure method of the above embodiment, an image of an isolated pattern such as a twin hole pattern can be exposed with high accuracy, and thus an electronic device can be manufactured with high accuracy.

The present invention can be applied not only to exposure with an immersion type exposure apparatus, but also to exposure with a dry exposure type exposure apparatus that does not use liquid.
The present invention can also be applied to a case where the progressive focus exposure method is applied to an EUV exposure apparatus that uses extreme ultraviolet light (Extreme Ultraviolet Light) having a wavelength of about 100 nm or less as exposure light. In the EUV exposure apparatus, the illumination optical system and the projection optical system are composed of reflective optical elements except for predetermined filters and the like, and the reticle is also of a reflective type.

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an imaging device (CCD or the like), a micromachine, a thin film magnetic head, a MEMS (Microelectromechanical Systems), and a DNA chip. Furthermore, the present invention can also be applied to an exposure process when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

  In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

  ILS ... illumination optical system, R ... reticle, CH1, CH2 ... CH (contact hole) pattern, RST ... reticle stage, PL ... projection optical system, PW1 ... image plane, W ... wafer, WST ... wafer stage, 2 ... main control System, 7B ... Aperture stop, 9 ... Fixed blind, 18W ... Exposure area, 22 ... Z tilt stage, 23A-23C ... Z drive unit

Claims (12)

In the exposure method of exposing the object through the mask and the projection optical system with exposure light by synchronously moving the mask on which the pattern is formed and the object in a predetermined direction,
In accordance with the asymmetric illumination characteristic of the exposure light with respect to the predetermined direction, the inclination angle of the exposure surface of the object with respect to the image plane of the projection optical system, and the moving direction of the object along the inclination direction of the exposure surface of the object A step of setting at least one of the exposure conditions;
Moving the object in the predetermined direction along the tilt direction while exposing the image of the pattern by the projection optical system onto the object tilted at the tilt angle with respect to the image plane; A step of synchronizing the movement of the mask in a direction corresponding to the predetermined direction along the object plane of the optical system, and exposing the object;
An exposure method comprising:   2. The exposure method according to claim 1, wherein the asymmetric illumination characteristic of the exposure light includes a width of defocus portions at both ends in the predetermined direction in an illumination region of the exposure light that illuminates the mask.   The exposure method according to claim 1, wherein the asymmetric illumination characteristic of the exposure light includes information on a light intensity distribution of the exposure light on a pupil plane of the projection optical system.   The exposure method according to claim 1, wherein the asymmetric illumination characteristic of the exposure light includes an asymmetry of a pupil plane of the projection optical system.   5. The step of setting the exposure condition sets the exposure condition according to information on asymmetric illumination characteristics of the exposure light and the shape of the pattern. An exposure method according to 1.   The step of setting the exposure condition sets the exposure condition according to an asymmetrical aberration component included in the imaging characteristics of the projection optical system. The exposure method according to item.   6. The exposure method according to claim 5, wherein the pattern shape information includes at least one of a direction corresponding to the predetermined direction of two rectangular patterns and an interval in a direction orthogonal to the direction. While exposing an image of the mask pattern by the projection optical system onto an object inclined at a predetermined inclination angle with respect to the image plane of the projection optical system, the predetermined direction along the inclination direction of the object inclined at the inclination angle is exposed. A mask used for exposing the object by synchronizing the movement in the direction and the movement of the mask along the object plane of the projection optical system and in a direction corresponding to the predetermined direction. ,
The shape of the pattern is corrected according to the asymmetric illumination characteristic of the exposure light with respect to the predetermined direction and at least one exposure condition of the tilt angle and the moving direction of the object along the tilt direction. Characteristic mask.   The mask according to claim 8, wherein the asymmetric illumination characteristic of the exposure light includes a width of defocus portions at both ends in a direction related to the predetermined direction in the illumination region of the exposure light.   The correction of the shape of the pattern is performed according to asymmetric illumination characteristics of the exposure light, the exposure condition, and information on the shape of the pattern before correction. mask of.   The said mask contains two rectangular patterns, The width | variety at least one of the direction corresponding to the said predetermined direction of at least one of the said two rectangular patterns and the direction orthogonal to this direction is correct | amended. 10. The mask according to 10. Forming a pattern of a photosensitive layer on a substrate using the exposure method according to any one of claims 1 to 7;
Processing the substrate on which the pattern is formed.

Images